The code is rewritten as follows, to make the lock more "fine grained" by moving the "other stuff" out of the critical section. Suppose that f and g are only changed in the code shown. // Thread 1 lock (m); f=&g; printf("%d, ", *); unlock (m); // do some other stuff lock (m); printf("%d ", *f); unlock (m); What are all the possible outputs of the system now? // Thread 2 lock (m); f = NULL; g= 11; unlock (m);